Molecular analysis of the En/Spm transposable element system of Zea mays

The nucleotide sequence of the autonomous transposable element En-1 isolated from the wx-844::En-1 allele has been determined. En-1 is 8287 bp long. The structure of the mosaic gene 1, coding for the major En transcript, has been established. The promoter gene 1 is located in the highly structured left end of the element and the gene spans almost the entire length of En-1. The first intron of gene 1 is 4434 nucleotides long and contains two large open reading frames, 2714 bp and 761 bp in size, which hybridize to minor RNA species in Northern blot experiments.

Early T-cell features in blast crisis of Ph1-positive chronic myeloid leukaemia

A patient with Ph1-positive chronic myeloid leukaemia (CML) presented in extramedullary blast crisis. Whereas the peripheral blood and bone marrow features were consistent with the chronic phase of CML, study of the enlarged lymph nodes demonstrated massive replacement by Ph1-positive blast cells of lymphoblastic morphology. Such blast cells showed diffuse acid phosphatase positivity, were positive for TdT, and had an enzyme pattern (adenosin-deaminase, purine-nucleosidephosphorilase and lactate-dehydrogenase) typical of immature T-cells. To further characterize the phenotype of the blast cells, they were analyzed for surface markers using a panel of monoclonal antibodies selected to identify differentiation antigens of T cells, B cells and myeloid cells. The results of the latter analysis were consistent with an early T-cell origin of the blast cells, since they were positive for TdT, CRIS1 (T1), E rosettes and OKT10, and were negative for OKT3, Leu3 and OKT8. These features demonstrate that T-cell markers may also be expressed in blast crisis of CML and provide evidence that T-cells may share a common stem cell with myeloid and B-cells in CML.

Molecular cloning of the a1 locus of Zea mays using the transposable elements En and Mu1

The a1 locus of Zea mays has been cloned using transposable elements as gene tags. The strategy was to make genomic libraries from maize stocks with a1 mutations induced either by En(Spm) or by Robertson's Mutator-system. These libraries were then screened with either Spm-I8 and En1, for the En-containing mutant, or with Mu1 for the Mu-induced mutation. There are many En and Mu1 hybridizing sequences present in the maize genome, however, by a process of cross-screening of the positives from the two libraries and by molecular analysis of the En-positive clones it was possible to identify clones in both libraries carrying all or part of the a1 gene.

Sequential appearance of immunoblastic lymphoma and acute nonlymphocytic leukemia in a patient with angioimmunoblastic lymphadenopathy

Immunoblastic lymphoma developed in a patient diagnosed as having angioimmunoblastic lymphadenopathy 5 years earlier. Chemotherapy schedules including alkylating agents were administered for 1 year, resulting in subsequent remission of the lymphoma. Thirty months after the start of chemotherapy, preleukemic changes were observed in peripheral blood and bone marrow, and acute nonlymphocytic leukaemia (M5 of the FAB classification) was diagnosed shortly afterwards. The possible role of both chemotherapy and the immunodeficiency associated to angioimmunoblastic lymphadenopathy in the pathogenesis of the leukemia is discussed.

Genetic and molecular analysis of the Enhancer (En) transposable element system of Zea mays

A newly isolated, unstable mutation wx-844::En-1 of Zea mays was proven to be caused by the insertion of the autonomous transposable element En into the Waxy (Wx) gene. Molecular analysis revealed that En-1 is 8.4 kb long, has a 13-bp long perfect inverted repeat at its termini and generates a 3-bp target site duplication. En-1 is integrated into an intron located approximately in the middle of the transcribed region of the Wx gene. Structural evidence is presented indicating that a receptor component (Inhibitor) can arise by internal deletion of an autonomous En element.

[Transient cortical blindness after cerebral angiography: report of a case]

A case of temporary cortical blindness following cerebral angiography is presented and discussed. The etiology of this rare complication is not completely understood. Probably the blindness is secondary to the direct effect of the contrast medium in the blood-brain-barrier in the striate cortex.

Mononuclear cell-mediated enhancement of granulocyte function in man

Human monocyte-enriched mononuclear cells (MNC) (greater than 95% monocytes) powerfully stimulated the antibody-dependent killing of tumor cells by purified human neutrophils (NE) or eosinophils (EO). The enhancement was observed when the mononuclear cell to granulocyte ratio was as low as 1:100. Media conditioned by MNC also stimulated antibody-dependent killing by NE and EO as well as the uptake and killing of Candida albicans by NE. There was a heterogeneity amongst individuals in the capacity of their MNC to elaborate this factor, and approximately 15% of individuals did not produce detectable factor. Different factors in the MNC supernatant were involved in NE and EO activation. The EO-activating factor (AF) had a m.w. of approximately 27,000 and migrated as a single band on phenyl-Sepharose chromatography. The NE-AF had a m.w. of 22,000 and migrated as two distinct bands on phenyl-Sepharose chromatography. EO-colony-stimulating factor (CSF) co-purified with EO-AF, and granulocyte-macrophage-CSF co-purified with both bands of NE-AF. It is concluded that MNC elaborate CSF-like molecules that powerfully stimulate human granulocyte function.

Mononuclear cell-mediated enhancement of granulocyte function in man

Human monocyte-enriched mononuclear cells (MNC) (greater than 95% monocytes) powerfully stimulated the antibody-dependent killing of tumor cells by purified human neutrophils (NE) or eosinophils (EO). The enhancement was observed when the mononuclear cell to granulocyte ratio was as low as 1:100. Media conditioned by MNC also stimulated antibody-dependent killing by NE and EO as well as the uptake and killing of Candida albicans by NE. There was a heterogeneity amongst individuals in the capacity of their MNC to elaborate this factor, and approximately 15% of individuals did not produce detectable factor. Different factors in the MNC supernatant were involved in NE and EO activation. The EO-activating factor (AF) had a m.w. of approximately 27,000 and migrated as a single band on phenyl-Sepharose chromatography. The NE-AF had a m.w. of 22,000 and migrated as two distinct bands on phenyl-Sepharose chromatography. EO-colony-stimulating factor (CSF) co-purified with EO-AF, and granulocyte-macrophage-CSF co-purified with both bands of NE-AF. It is concluded that MNC elaborate CSF-like molecules that powerfully stimulate human granulocyte function.

[Modulation of the lymphocyte membrane with anti-HLA ABC in psoriasis]

Antibodies against lymphocyte surface antigens are able to rearrange the topographic of the cell membrana. This is the first event of immune cell functions for motility and cell adherence. Take in account: the high incidence of some HLA antigens in psoriasis and that the HLA system is involved in the genetic control of immune responses, we studied the reaction of anti HLA antibodies against lymphocytes from 16 patients with active psoriasis and from six healty controls. For this: lymphocytes T or B are sensitized with optimal amounts of anti HLA ABC antibodies. They are washed and resuspended in a nutrient medium and incubated at 37 degrees C. At 0, 3, 4, 5 and 6 hours samples are taken and observed for microlymphocytoxicity after addition of complement. Controls for viability and for antigenic sites are made. The addition of complement shows a decrease in the cytotoxic reaction. This is due to the loss from the cell surface of the antigen-antibodies complexes. The observed phenomenon is paralleled to the rearrangement of membrane proteins and is developed in a similar period to the normal antigen turnover time. Our results demonstrate a significative decrease in the turnover for HLA ABC molecules at the cell surface of T lymphocytes from psoriasic patients, that we assimilate to an altered rearrangement of HLA ABC molecules. No significative differences was observed for the turnover of HLA ABC molecules at cell surface of B lymphocytes. The altered T lymphocyte membrane demonstrate an immunobiologic defect and it may the explanation for the impairment for the T cell function in psoriasis.(ABSTRACT TRUNCATED AT 250 WORDS)

Modulation of a neural antigen during metamorphosis in Drosophila melanogaster

Major reorganization in the central nervous system (CNS) takes place during metamorphosis in holometabolan insects (G. Technau and M. Heisenberg, 1982, Nature (London) 295, 405-407. J. W. Truman and S. E. Reiss, 1976, Science 192, 477-479). In this report, two monoclonal antibodies specific for antigens localized in the CNS of Drosophila melanogaster are utilized to examine the behavior of these neuronal antigens during metamorphosis. One of the antigens studied is concentrated in synaptic areas of the CNS in adults and larvae. The other antigen is more ubiquitously distributed, being present in both cortical and synaptic regions. Metamorphosis is accompanied by dramatic change in the concentration of the antigen localized to synaptic areas. In contrast, the ubiquitously present antigen persists throughout.

In vitro development of resistance to nystatin by Candida albicans and Torulopsis glabrata

The levels of resistance to nystatin induced in 16 strains of Torulospsis glabrata by a few subcultures in the presence of the drug were high (minimum inhibitory concentrations > 20 000 U ml-1) compared with those obtained in 12 strains of Candida albicans (minimum inhibitory concentrations less than or equal to 2000 U ml-1). The results suggest a high rate of mutation in the first species.